Abstract
Prenylated FMN (prFMN) is a recently discovered modified flavin cofactor containing an additional non-aromatic ring, connected to the N5 and C6 atoms. This cofactor underpins reversible decarboxylation catalyzed by members of the widespread UbiD-enzyme family, and is produced by the flavin prenyltransferase UbiX. Oxidative maturation of the UbiX product prFMNH2 to the corresponding oxidized prFMNiminium is required for Fdc1 (a UbiD-type enzyme) activity. However, it is unclear what role the Fdc1-enzyme plays in this process. Here we demonstrate that in the absence of Fdc1, prFMNH2 oxidation by O2 proceeds via a transient semiquinone prFMNradical species and culminates in a remarkably stable prFMN-hydroperoxide species. Neither forms of prFMN are able to support Fdc1 activity. Instead, enzyme activation using O2-mediated oxidation requires prFMNH2 binding prior to oxygen exposure, confirming that UbiD-enzymes play a role in O2 mediated oxidative maturation. In marked contrast, alternative oxidants such as potassium ferricyanide support prFMNiminium formation both in solution and in Fdc1.
Original language | English |
---|---|
Journal | ACS chemical biology |
Publication status | Accepted/In press - 25 Aug 2020 |
Research Beacons, Institutes and Platforms
- Manchester Institute of Biotechnology